Vincenzo Nibali is on the brink of a maiden Tour de France crown after coming through Saturday's time-trial unscathed, finishing fourth behind German Tony Martin.

With only Sunday's ceremonial ride into Paris to come, Nibali extended his overall lead to seven minutes and 52 seconds after overcoming the 54-kilometre penultimate stage between Bergerac and Perigueux with minimal fuss.

The Italian will wear the yellow jersey for the 18th day on Sunday as the Tour concludes in Paris and will triumph by the biggest margin since Jan Ullrich won by nine minutes and nine seconds in 1997.

The Astana rider will be joined on the podium by two Frenchmen after Jean-Christophe Peraud climbed to second overall ahead of compatriot Thibaut Pinot despite the former suffering a puncture halfway through. It will be the first time in 17 years that a home rider will finish in the top three and the first time in 30 years that two will finish on the podium.

Omega-Pharma Quickstep rider Martin completed the hilly course in a time of one hour, six minutes and 21 seconds to claim his second stage win of the Tour.

Nibali is the first Italian since 1998 to win the prestigious race and becomes the sixth rider to win all three Grand Tours after triumphing at the Giro d'Italia and Vuelta a Espana.